We have recently acquired a state-of-the-art triple quadrupole mass spectrometer fitted with an electrospray ionization ion source. The instrument allows the investigation of the collision-induced dissociation of selected ion species. We are investigating the quality and dependence of the fragmentation data obtained from peptides as a function of parameters such as collision gas density and ion energy. The findings are of both fundamental and practical interest. A paper describing our findings is in the final stages of preparation.